JR39857: CMVC 211361 - REMOVE UNNECESSARY DATA CACHE INVALIDATION WITH OUT-OF-THE-BOX CONFIG.

APAR status

• Closed as program error.

Error description

• The data cache is enabled by default when your instance is
  created.  The data cache can be enabled even if it has not been
  configured to cache data.  If the data cache is enabled, when
  data changes, the data cache issues DynaCache invalidation
  messages via the Domain Replication Service.  Those invalidation
  messages are always sent when the data cache is enabled,
  regardless of whether the system has been configured to cache
  data or not.  The messages are only used when the cache is
  configured to cache data.  The result is that if the data cache
  has not been configured to cache objects (as it is right after
  an instance creation), the data cache issues unnecessary
  invalidation messages when the data is modified.  These
  unnecessary invalidation messages can be the source of
  performance degradation when the Replication Domain has a large
  number of nodes.
  

Local fix

• If the data cache is not being used at all, it can be explicitly
  disabled in the InstanceProperties tag of the wc-server.xml
  instance configuration file, like this:
  
  <CrossTransactionCache enabled="false"/>
  
  Or, if only some logical caches are being used, the ones that
  are not being used can be explicitly disabled in the
  wc-server.xml instance configuration file.
  
  For detailed information, see the following links:
  
  Additional WebSphere Commerce data cache configuration
  http://publib.boulder.ibm.com/infocenter/wchelp/v7r0m0/topic/com
  .ibm.commerce.admin.doc/concepts/cdcaddcomdatcacheconfig.htm
  
  Logical cache names and the DistributedMaps they use by default
  http://publib.boulder.ibm.com/infocenter/wchelp/v7r0m0/topic/com
  .ibm.commerce.admin.doc/refs/rdclogcachnameDM.htm
  

Problem summary

• USERS AFFECTED:
  All WebSphere Commerce customers.
  
  PROBLEM ABSTRACT:
  Unnecessary invalidation messages are issued via DRS when the
  data cache is not used and is not explicitly disabled.
  
  BUSINESS IMPACT:
  Possible performance degradation.
  
  RECOMMENDATION:
  

Problem conclusion

• During server startup, each logical cache registers it's need to
  receive invalidation messages.  This fix delays the registration
  for certain user or session related logical caches until each
  logical cache actually caches some data.  This should prevent
  unnecessary invalidation messages for logical caches which are
  not configured to cache data.
  
  This fix assumes that session affinity is enabled.
  
  If for some reason it becomes necessary to revert back to the
  old behavior, add the following line to the InstanceProperties
  tag of the wc-server.xml instance configuration file:
  
  <CrossTransactionCache delayInvalidationRegistration="false" />
  
  -------------------------------------------------------------
  The latest available maintenance information can be obtained
  from the Recommended Fixes for WebSphere Commerce technote:
  http://www.ibm.com/support/docview.wss?rs=3046&uid=swg21261296
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WC BUS EDITION

• Fixed component ID

  5724I3800

Applicable component levels

• R700 PSY

     UP